Calibration contestLet's try a different contest. Here the focus will be fine tuning the output dimensions of a printed part.
I'll be happy to buy the winner a 100m roll of his choice of filament in fabberdashery webshop, shipping included - subject to conditions, see later.
So the goal is to print the attached stl, and have the dimensions noted in the following picture as close to theory as possible. An incremental process - print, change settings, print again - will probably be needed.
As a rule, no dimensional modification of the file to print is allowed (rotation is ok). You must improve your output by tweaking your settings, not the stl.
There must be some infill, print the stl as if you would be going to use it as a structural part of a reprap.
You obviously will need a digital caliper or any tool able to measure as little as 0.01 mm.
If you want to participate in the competition for the price, you'll have to :
1) Post here describing your process and the changes you made to improve your accuracy. Pictures are welcome.
2) Send me your best part for verification (send me a PM to get my postal address).
3) Use a reprap derivative, fused deposition, no resin or powder printer, or industrial expensive machinery. Please post your machine specs, a picture would be nice too.
If you have access to and want to use such a non-reprap printer, feel free to give it a try, would be nice for comparison, but understand that you can't enter the competition then.
The most important dimensions for me are the 2 inner 20 mm, as the goal is to fit a given extruded aluminium profile. It is also better to be a little under 20mm than above (to keep some grip).
The second most important dimension is the 1.5 mm gap.
External dimensions accuracy and best looking parts will get bonus points in case of a tie.
If there are too many perfect or nearly perfect prints to decide, I'll pick a random part among the pool to choose the winner.
You can post your participation here until the 15th of november. I must have received your best part before the end of november (2012 of course).
Note : this contest also have an hidden agenda, my goal is to have more people ready to help Emmanuel in his crowd-printing experiment, see http://forums.reprap.org/read.php?95,158212
I'll post a sample of what I expect as a submission post after the weekend.
[img]http://forums.reprap.org/file.php?282,file=10193,filename=Contest.png[/img]https://reprap.org/forum/read.php?282,159683,159683#msg-159683
Mon, 21 Jan 2019 17:00:16 -0500Phorum 5.2.23https://reprap.org/forum/read.php?282,159683,171895#msg-171895Re: Calibration contesthttps://reprap.org/forum/read.php?282,159683,171895#msg-171895
Here my screw extruder.... but... in italian..... sorry....]]>immaginaecreaCompetitionsMon, 17 Dec 2012 11:22:50 -0500https://reprap.org/forum/read.php?282,159683,167756#msg-167756Re: Calibration contesthttps://reprap.org/forum/read.php?282,159683,167756#msg-167756
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> Nice result immaginaecrea.

Thank you my friend
>
> And unusual machine ! Is that a screw extruder ?

#4 (bonus, shown bent) is printed with normal settings in soft pla. I'm pretty sure it would be easy to slide on the profile, but on the other hand it might not provide a rigid structure... (Thanks to Gregory for lending me a hand - literally - for the picture). Dimensions are variable as the plastic flex..

Note to Emmanuel : still planning to send you those parts asap.]]>DeuxVisCompetitionsWed, 21 Nov 2012 16:27:09 -0500https://reprap.org/forum/read.php?282,159683,166317#msg-166317Re: Calibration contesthttps://reprap.org/forum/read.php?282,159683,166317#msg-166317
As for me the only improvement I was able to obtain is by reducing the E_STEPS a bit.

At minus 5 % I have better dimensional accuracy with a good skin, If I go down to 10% the dimensions are still better but the surface infill starts to look bad because of the lack of plastic.

Will post photos later.

Thank you all for showing your prints/sharing your tips.]]>DeuxVisCompetitionsThu, 15 Nov 2012 11:02:30 -0500https://reprap.org/forum/read.php?282,159683,162591#msg-162591Re: Calibration contesthttps://reprap.org/forum/read.php?282,159683,162591#msg-162591
Tonight I even managed to get quite close to my Skeinforge results !!! (previously unmatched with any version of Slic3r)

This time I tried to use the same key settings I had in Skeinforge.

A 101% scale, the 0.38 extrusion (even if it's for free extrusion I wanted to try), then the 0.48 pwot and 0.489 iwot (since it's 1.6 and 1.63 in skeinforge ratio's)

left : SF47
middle : defaut-slic3r
right : slic3r-038
red is with my huxley1, blue with the huxley 2

(huxley1_SF47 : dead on as seen in my previous post)
huxley1_default-slic3r : good but... 19.95-19.96 / 1.48-1.60
huxley1_038.gcode : better ! 19.97-20.05 / 1.46-1.60 it even look like the skeinforge one
huxley2_038.gcode : very good 19.95-20.05 / 1.46-1.55

The results are promising for me in that mean I can use Slic3r more often for the precise parts :)]]>EmmanuelCompetitionsWed, 24 Oct 2012 13:55:09 -0400https://reprap.org/forum/read.php?282,159683,161519#msg-161519Re: Calibration contesthttps://reprap.org/forum/read.php?282,159683,161519#msg-161519
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> Thanks richgain, that looks promising, are the
> bolts still very loose (I think the design was
> like that) your first layer also looks a little
> too squished. I'm going to make the switch to
> 0.9.3 then.

I had real trouble getting this Faberdashery green to stick to the bed (all the other colours in the Rainbow pack have been fine). In the end I had to turn the heat up to 80 and lower the nozzle til it was almost touching the glass.
The bolts are just right. Not loose at all but I was able to do them all up without any clean up or using tools. I was amazed at how well the fairly primitive looking threads worked.]]>richgainCompetitionsThu, 18 Oct 2012 15:22:38 -0400https://reprap.org/forum/read.php?282,159683,161504#msg-161504Re: Calibration contesthttps://reprap.org/forum/read.php?282,159683,161504#msg-161504
I ran the test piece through Slic3r 0.91 and Kisslicer with as close to similar settings as possible and what's apparent is the flowrate calculations don't match, Slic3r seems to over extrude at the same settings as Kisslic3r, Kisslic3r also produces a better surface finish, which I think is likely due to the expected overlap between the solid infil and the perimeters.

My experience with Slic3r 0.91 is it's OK, though I've gone back to using Kisslic3r for anything but the simplest of prints. I only use Slic3r for those because it's integrated into repetier host and it's quicker.]]>PolygonhellCompetitionsThu, 18 Oct 2012 14:24:35 -0400https://reprap.org/forum/read.php?282,159683,161495#msg-161495Re: Calibration contesthttps://reprap.org/forum/read.php?282,159683,161495#msg-161495
I have a few standard test parts (one is a herringbone gear set) that should tell me if it's as accurate as 0.9.1

And thanks Sublime, I will experiment when the Tantillus is alive - Really love the extruder BTW, the tiny Fish-bone gears are a nice print to see come out of my machine!]]>richrapCompetitionsThu, 18 Oct 2012 13:36:14 -0400https://reprap.org/forum/read.php?282,159683,161469#msg-161469Re: Calibration contesthttps://reprap.org/forum/read.php?282,159683,161469#msg-161469
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> @Emmanuel & richgain - Are you both happy with
> Slic3r 0.9.3? I have only been using 0.9.1 and not
> yet made the jump to 0.9.3, do you see any
> problems?

@richrap
I'm much happier with 0.9.3 than any of the other recent versions of Slic3r, so much so that I decided to have another go at the 'Tiny planetary gears' which I failed to print before. It's not the best copy in the world but it definitely works.

No they have far to many bugs, geometry errors and the path planning is horrible which makes for to many retracts. Version 0.7.2b only has two small bugs I know of and they are easy to work around. I have altered Slic3r 0.7.2b to have a bunch of special retract settings brought out called it Slic3T. It works well but I have introduced a bug that will not let 0.1 and lower layers. So far though the testing with 0.15 and 0.2 have been promising.]]>SublimeCompetitionsMon, 15 Oct 2012 04:46:17 -0400https://reprap.org/forum/read.php?282,159683,160755#msg-160755Re: Calibration contesthttps://reprap.org/forum/read.php?282,159683,160755#msg-160755
@sublime - Are you happy with any newer versions above 0.7.2b for Tantillus yet? I hope to be commissioning it soon.]]>richrapCompetitionsMon, 15 Oct 2012 04:36:48 -0400https://reprap.org/forum/read.php?282,159683,160689#msg-160689Re: Calibration contesthttps://reprap.org/forum/read.php?282,159683,160689#msg-160689
Unfortunately, I forgot that PLA really needs a cooling fan. The result wasn't usable but as well as being warped from over-heating, I could see that I was still over-extruding plastic.

I repeated the print with the ducted fan switched onto a low setting. I also reduced the feed-rate to 80% (printing more slowly to allow time for the layers to cool) and the flow-rate to 85% (a figure that seems to work best for me) in Repetier Host, based on the apparent over-heating and over-extrusion in the first print.
This one came out much better: 28.06/28.08; 19.90/20.01; 1.49/1.49/1.49/1.48.

I've not yet managed tweak Slic3r to match the results I have with Skeinforge, but things are improving...
I'll try to see if I can invert the profiles between the machines, since they are supposed to be the same (except a little different gear ratio).]]>EmmanuelCompetitionsSun, 14 Oct 2012 09:05:11 -0400https://reprap.org/forum/read.php?282,159683,160576#msg-160576Re: Calibration contesthttps://reprap.org/forum/read.php?282,159683,160576#msg-160576
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> @richrap - Yes, still using the original
> resin-cast pulleys on X and Y on the Huxley.
> What's your experience of them?
> No, I'm planning to try on the Mendel90 some time
> today. Will update when it's ready.
> For quality and tolerance, I've always found the
> Huxley more accurate, probably because of the
> finer nozzle and lightweight Bowden-fed
> printhead.
> This should be an interesting test.

The cast ones worked well for a while, I'm not sure if they changed shape or wore down, but over time I noticed a difference in the Y axis and switched to metal ones. I use metal on all my machines now. I do tend to have my belts very tight.

The flow is a little low, I may increase the flow by 5-10 steps per mm.

I used the standard coarse 0.5mm Tantillus Slic3r 0.7.2b profile available [github.com]]]>SublimeCompetitionsSun, 14 Oct 2012 01:02:35 -0400https://reprap.org/forum/read.php?282,159683,160528#msg-160528Re: Calibration contesthttps://reprap.org/forum/read.php?282,159683,160528#msg-160528
You could set the top one (default) to the width you want and it will use it on any of the other ones with a zero. Or you can change them all individually.]]>SublimeCompetitionsSat, 13 Oct 2012 18:04:02 -0400https://reprap.org/forum/read.php?282,159683,160525#msg-160525Re: Calibration contesthttps://reprap.org/forum/read.php?282,159683,160525#msg-160525

]]>Wired1CompetitionsSat, 13 Oct 2012 17:41:47 -0400https://reprap.org/forum/read.php?282,159683,160518#msg-160518Re: Calibration contesthttps://reprap.org/forum/read.php?282,159683,160518#msg-160518
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> I'm just learning how to change the nozzle
> diameter instead of the extrusion multiplier, as
> recommended by Richrap, which should give me even
> better control over print accuracy.

This is not actually the case. I am the one that came up with this method of improving prints but you will still have to adjust the extrusion multiplier to get the flow correct. Telling it you have a smaller nozzle makes slic3r produce a narrower path but it also reduces the flow to match so it will have no effect on actual flow vs feed. This improves prints and makes them more accurate by printing closer to the actual nozzle diameter. When you print as wide as Slic3r wants to with the correct nozzle diameter entered you get holes that turn out WAY to small, blobs on the corners and really round corners instead of sharp ones.

For a J-head I have found you want to print NO WIDER than 0.2mm wider than the advertised nozzle diameter. and for really low layers 0.15 and less you want to print the same width as the advertised nozzle diameter and as much as 0.2mm less then advertised nozzle diameter for 0.1mm layers.

That'll do for today.]]>richgainCompetitionsSat, 13 Oct 2012 13:33:37 -0400https://reprap.org/forum/read.php?282,159683,160488#msg-160488Re: Calibration contesthttps://reprap.org/forum/read.php?282,159683,160488#msg-160488
When you tell slic3r what layer height and wall thickness you want, it will try its best to achieve those settings by controlling the speed of the nozzle across the build platform (feed-rate) and the rate of extrusion (flow-rate).
However, it bases its calculations on a formula that takes into account the input filament diameter, the nozzle diameter and the extrusion multiplier.
Originally, I concentrated all my attention on finding the best extrusion multiplier for any given print (which is affected by all the above parameters, and probably also other things like material type/brand and nozzle temperature).
If there are gaps in your top layer, increase the extrusion multiplier by 1 or 2 %.
If the top fill layer starts to lift above the set height, and especially if the non-printing movement of the head leaves a trail as it drags through excess plastic, decrease the multiplier a little. (I had lots of problems like this when I started printing a year ago as this early print demonstrates.)

I used to have to set this value in Gcode, do a test print, change the value again, iterate many times, until I found a value (or range of values) that worked well. Now, as I said before, I can greatly speed up the process by tweaking the flow-rate on the fly. I usually specify 4 solid layers at the bottom of the print, which gives me plenty of time to watch how the solid fill is progressing and increase or decrease the flow-rate as required.

Hi Richgain, do any of these settings you posted, contribute to your very nice top layer, its full fill and even, I tend to end with spacing between the extrusions on top, any other pointers you could offer?

Also, this looks like fun, I'll give a print a try tomorrow]]>JaramaniacCompetitionsSat, 13 Oct 2012 08:51:50 -0400https://reprap.org/forum/read.php?282,159683,160396#msg-160396Re: Calibration contesthttps://reprap.org/forum/read.php?282,159683,160396#msg-160396
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> @richgain - No problem, glad it helped. That's
> looking really great!
>
> Do you have the original cast X/Y pulleys on the
> Huxley? or metal ones?
>
> Have you also printed it on the Mendel90 to
> compare?

@richrap - Yes, still using the original resin-cast pulleys on X and Y on the Huxley. What's your experience of them?
No, I'm planning to try on the Mendel90 some time today. Will update when it's ready.
For quality and tolerance, I've always found the Huxley more accurate, probably because of the finer nozzle and lightweight Bowden-fed printhead.
This should be an interesting test.]]>richgainCompetitionsSat, 13 Oct 2012 01:58:02 -0400https://reprap.org/forum/read.php?282,159683,160365#msg-160365Re: Calibration contesthttps://reprap.org/forum/read.php?282,159683,160365#msg-160365
Measures 28.29/19.85 on one side and 27.88/19.61 on the other and internals are 1.4/1.51/1.35/1.48
Last print was in yellow which prints neater than the white plus I changed the nozzle to 0.3mm and applied an 85% extrusion multiplier.
Thanks the the contest idea Deux, it has made me get my printer a lot more accurate and will help the quality of my prints.